Promises Kept (A Hunter x Hunter One Shot)
by Kirbydesu248
Summary: Sequel to "Human". Hisoka keeps a close watch over Killua and Alluka, keeping a secret vow he made years ago. When Killua is under the weather, Hisoka's true motives come to light.


"Alright, how many _fucking_ times do I have to tell you to back off?" Killua seethed pushing Alluka behind him before spinning on his heels to face Hisoka. Hisoka simply raised an eyebrow from where he stood, perched against a wall. Those nearby enjoying the market turned a questioning gaze toward them.

"Now, now, Killu. You're causing a scene." Hisoka said nonchalantly, pulling out a stick of gum before placing it in his mouth.

"Don't call me that." Killua spat, his eyes narrowed. "Why do you keep following me? I told you I'm not taking Alluka back. And _I'm_ not going back. So you can tell Illumi to shove it."

"You have a filthy mouth. Did you pick that up from Gon? Or did he get it from you?" Hisoka blew a bubble, walking closer to the teen while keeping a comfortable distance. "And I'm just here enjoying the market like everyone else. I wonder if they have any Bungee Gum…"

Killua's eyebrow twitched. "Get lost. And quit following us. I'm getting real sick of it." He clutched Alluka's hand and dragged her into the swarm of people looking at various booths. He kept his eyes ahead as Alluka glanced back at Hisoka.

"Big Brother, who was that? Why does he keep following us?" Alluka asked innocently, looking up at her brother.

"Just don't look at him. Maybe he'll go away." Killua muttered as he dragged her along.

Hisoka sighed, his eyes narrowed as he slowly started walking in the direction the teens had run off in. _Amari, this boy is really getting on my nerves._ He shook his head walking along, weaving through the crowd.

…..

"M-Mister! You have to help! Please!"

Hisoka opened his eyes, raising his eyebrows when he saw Alluka running toward him with a panicked expression. _Hm? Where's Killua?_ His eyes widened slightly and he sat up a little straighter on the bench. The girl looked at him with tears in her eyes as she grabbed Hisoka's hand, tugging at it.

"B-Big Brother won't wake up! And h-he's hot!" Alluka whimpered, trying to pull him to his feet, "I-I know Big Brother doesn't like you very much. B-But something's wrong! You have to help!"

"Alright, alright. Calm down. Where is he?" Hisoka said, relaxing a bit. _At least he's only sick._

"O-Our hotel room." Alluka whimpered again, and Hisoka smiled down at her before standing.

"Lead the way. I'll do what I can." Hisoka said calmly, a smile on his lips. She beamed, excited that he was willing to help her brother.

"'Kay!" She dragged her towards the hotel that her and Killua had been staying in, leading him to their room.

Hisoka frowned when he saw Killua curled up in bed, his face contorted in pain and his face tinged pink from a fever. He placed a hand on his forehead noting that he did indeed have a fever, pulling the sheet loosely up to his chest.

"H-He's been like this all morning. Is he going to be okay?" Alluka asked, her voice thick with more tears. Hisoka turned to her, ruffling her hair.

"He'll be just fine. He has a fever, so just needs rest." Hisoka said matter-of-factly, turning to leave when he felt a pull on his shirt. He looked over at Alluka with eyebrows raised.

"Please, mister clown man sir," Alluka pouted. Hisoka's eyebrow twitched.

 _Mister clown man sir? Easy, Hisoka. Killing a little kid is frowned upon. And since she's Killua and Illumi's sister, that wouldn't go over well._

"I don't know how to take care of him… I would just do it wrong and brother would get sicker and—"

"Okay, okay!" Hisoka sighed rubbing his temples, "Just… sit down and watch cartoons."

"Thank you so much!" Alluka said hugging Hisoka around his waist. He stiffened, not used to the affection. He awkwardly pulled her away by her head. She tilted her head to the side, "You're funny, clown man."

"My _name_ is _Hisoka_." His eyes narrowed at her as she giggled. "Now go watch tv while I take care of your brother."

"'Kay!" She giggled, sitting on the other bed and turning on the tv. She stole a glance at him every once and awhile and it took all of Hisoka's willpower not to knock her unconscious.

He sighed as he walked to the bathroom, getting a cloth and wetting it before returning to Killua's side and placing it on his head. He looked at the unconscious Zoldyck boy with a frown on his face. It truly was a pitiful sight. The boy looked so _weak_. So defenseless. Illumi could just waltz right in there and take them back home if he wanted to. _Pathetic_.

Killua whimpered in his sleep and Hisoka's frown deepened. _It turns out that even assassins can get sick._ Killua shifted, turning his face, the cloth falling off onto the mattress. Hisoka quickly returned it to its rightful place, adjusting the angle so that it wouldn't fall off this time. He adjusted the blanket around Killua again before sighing deeply. _Looks like I'm stuck here for a bit._ He knew that he could very well leave any time he chose to, but something was holding him back. He sank into the desk chair, absentmindedly watching the cartoon that Alluka was watching.

It was dark when Killua sat up abruptly, the cloth falling off his face and onto the floor. He looked around in a daze, the fever not yet gone. When his eyes landed on Hisoka still sitting by the desk, he gave him a weak glare.

"Hisoka! What are you—"

The older man cut him off, putting a finger to his own lips before pointing to Alluka asleep on her bed. He walked closer to Killua, slowly as to not startle him further. Killua tensed anyway, watching him like a hawk.

"What are you doing here, Hisoka? I told you I'm not going back." Killua tried to be stubborn, the fever making it difficult to think. He flinched when Hisoka placed a hand on his forehead before pushing him back on the bed gently.

"You still have a fever. You need more rest." He said soothingly and replaced the cloth on Killua's head. Killua tried to keep watching him but his eyes felt heavy.

"Why are you doing this?" Killua mumbled tiredly, his eyes drooping. Hisoka pulled the blanket back over him, watching as his chest rose and fell.

"I'm just keeping a promise I made." Hisoka mumbled under his breath before sitting back down, watching the tv.

…..

"Big Brother! You're awake! How are you feeling? Do you need anything?" Alluka ran from her spot on her bed over to Killua's bedside as he sat up.

"A-Alluka…" He smiled softly, patting her head. "I'm feeling alright. Thank you."

"That's good to hear." Hisoka spoke from the foot of Alluka's bed, a pleasant smile on his face as he offered a wave. "You slept a long time."

"Hisoka!" Killua glared, jumping up out of bed with his fists clenched. "So it wasn't a dream. What do you want?"

"You sure ask that a lot." Hisoka frowned, "What if I just wanted to see one of my favorite fruits back to health?"

"S-Stop being creepy! You've gotta have some reason for being here. So why? Did you call Illumi? Is he—"

"Illumi doesn't know I'm here. And I have no plans of taking you or your sister back to him. So relax." Hisoka pulled out a deck of cards, shuffling them absentmindedly, "I'm here on my own accord."

"So why then?" Killua asked, eyeing him suspiciously. "If you aren't helping my brother and he didn't put you up to this, then why'd you help me?"

"I'm keeping a promise." Hisoka said, his fingers moving deftly as they shuffled. Alluka watched how quickly the cards moved mesmerized.

"A promise?" Killua raised his eyebrows. "What the hell is that supposed to mean?"

"…" Hisoka's fingers stopped and a few cards dropped to the carpet. His eyes were unreadable to Killua's trained eye as he stared at wall, his mouth in a firm frown.

"Um, Hisoka?" Killua felt uncomfortable, sitting back down on his bed. Alluka looked at Hisoka concerned before giving her brother a puzzled look. He shrugged and tried again, "What promise?"

"That no matter what, I won't lose my sense of humanity." Hisoka replied, still staring at the wall, a far off look in his eyes. He was snapped out of his trance by Killua's laughter and looked at him in surprise.

"Y-Your _humanity_? You're the furthest thing from being human! You're just as crazy- hell, you're _more_ crazy than Illumi! At least it's his _job_ to kill. You kill just for the hell of it. And you expect me to believe you're helping me out to keep your _humanity_?"

"So? What's your point?" Hisoka's voice was nonchalant, but his eyes were narrowed in annoyance.

"That makes zero sense. You do realize that, right?" Killua said with his arms crossed.

"Big Brother, be nice!" Alluka glared, hugging Hisoka. Hisoka stiffened, surprised by the contact.

"Don't hug him, Alluka! He's not nice!" Killua yelling, flailing his arms.

"But he helped us!" Alluka countered.

"Th-That doesn't mean anything! He's a _bad guy_!"

"I don't believe you!" Alluka pouted, clinging tighter stubbornly. Hisoka blinked, unsure of what to do. He settled for hesitantly patting her head as he saw Killua do. Killua twitched exasperated, sighing.

"Alright, _fine_ , Hisoka. What did you mean by what you said? About the humanity stuff?" Killua said, glaring at the two.

"Well," Hisoka shifted, getting a bit more comfortable with the girl wrapping her arms around him. "You remind me of someone I once knew, someone who made me human."

"Really? I remind you of someone?" Killua perked up in interest, "Who?"

"My son." Hisoka said, rubbing Alluka's head. She looked up at him curiously, and he could feel Killua's eyes on him as well.

"You have a _kid_?" Killua said, surprised. He inwardly wondered what that poor kid did to deserve have a creep dad like Hisoka.

"Had." Hisoka's eyes met Killua's, a sadness in them. "He was killed by a rogue hunter." Killua's eyes widened in shock.

"W-Woah. I'm- I mean I didn't know…" Killua mumbled, feeling uncomfortable for his previous thoughts. Hisoka smiled a bit and Killua flushed, looking away. "A-Anyway, why do I remind you of him? I mean it can't be looks since you don't look anything like me."

"Your eyes." Hisoka stated and Killua looked back at him in shock.

"Huh?" Killua blinked at him. Hisoka looked back at him, thoughtful, and Killua felt self-conscious under his scrutiny.

"I can't explain it, but the look in your eyes reminds me of him." Hisoka frowned, "He was only a baby when he was killed, but I imagine he would have been something like you. I would hope for that, at least."

"Wh-Wha-" Killua flushed, scratching the back of his head. Alluka giggled at her brother's red face. He huffed looking away, his face still crimson. "C-Cut it out! That's weird! Why the hell would you want him to be like me anyway?"

"You protect your friends and your sister with your life. You left your family because you didn't want to be a killer." Hisoka smiled softly, "I would hope that Hotei would be just like that. That he would have a strong resolve."

"Was that his name? Hotei?" Killua asked after a moment, his voice quiet but curious. Hisoka nodded.

"When he and his mother were killed, I lost myself. I took care of the man who took them from me but at a cost. I guess that joke was on me, wasn't it?" Hisoka smiled bitterly. "I hired your family to kill him."

"Wh-What?" Killua watched him, intrigued.

"It's true. But Illumi brought you along and I panicked. Something about you made me remember. I didn't want you to lose yourself like I had." A few moments passed in silence with Killua processing the new information.

"Nothing's changed. You're still a psychotic creep. You still freak me out. And you're still a perv who has a thing for my best friend- don't deny it, it's obvious." Killua started, slowly looking back up at Hisoka.

"I'm not a pervert. I'm attracted to power- you and Gon just happen to have a lot of it." Hisoka pointed out.

"I'll ignore the fact that you mentioned me. Anyway, you're still a sicko that I want nothing to do with." Killua said evenly, his eyes hardened. Hisoka nodded.

"Fair enough."

"But," Killua hesitated, much to Hisoka's surprise, "I'm… sorry about your family. And thanks for helping Alluka and taking care of me… I owe you one, Hisoka."

Hisoka's eyes widened in slight surprise, the ends of his mouth twitching.

…

Killua groaned looking at his phone as he sat on the couch with Gon. Gon stopped talking, tilting his head to the side trying to see the phone. Killua quickly closed it, rolling his eyes.

"Who was it? Is Alluka alright?" Gon asked, leaning into his new found boyfriend slightly. Killua blushed, setting it on the table.

"She's fine. It wasn't her." Killua mumbled, his breath hitching as he felt lips on his neck.

"Who was it?" Gon pressed, nuzzling his nose along the smooth skin, grinning as he felt Killua shiver. Killua smirked, pushing Gon onto his back.

"None of your business, dummy." Killua's lips found Gon's as he straddled him, the teens moaning into the kiss.

Lips moved against each other, only being interrupted when tongues joined in. Tan arms wrapped around Killua's body as Killua's own hands found the spikes of Gon's hair. Chests pressed against each other and the only sounds came from their breathy gasps and moans- along with the insistent vibrating of Killua's phone. Their skin was flushed at the unfamiliar experience of new love, the excitement and anticipation of what was certain to come.

"Whaa-" The moment was broken as Killua was pulled back by an invisible force. He barely landed on his feet. He spun around facing Hisoka, holding a single finger in the air. Killua used gyo and saw a pink string connecting him to the man. "Wh-What the _hell_?"

"You really shouldn't ignore your phone when someone calls you. It's rude." Hisoka says disapprovingly, frowning.

"And _you_ shouldn't just barge in like that! W-We were… busy!" Killua flushed, equal parts angry and mortified. Hisoka looked around the blushing boy and waved to Gon, who was staring in shock with a face rivaling the shade of his boyfriend's.

"Ya, Gon. Long time no see." He smiled before scowling at Killua, "It was still rude."

"You're rude too! And I thought I told you not to keep stalking me! Alluka and I are _fine_. She's with a friend." Killua pointed to the doorway, "Now get out! And get that bungee gum off me!" Hisoka narrowed his eyes before releasing his nen.

"Alright," Hisoka smirked walking out the door, "Be safe you two."

"Wh-Wha- _Huh?_ " Killua flushed a deeper shade of red, "What the hell is _that_ supposed to mean, you perv?! Hey! Get back here!" Killua sprinted after him, leaving a confused Gon in his wake.

"Hisoka? Wh-What was Hisoka doing here?" Gon mumbled, his brain frying as he tried to process the ordeal.


End file.
